Engineering the magnetic properties of acrylonitrile butadiene styrene-based composites with magnetic nanoparticles

This work reports the engineering of the magnetic properties of composites based on acrylonitrile butadiene styrene (ABS) by the inclusion of different magnetic nanoparticles (MNP). ABS-based composites with different MNP, including permalloy, Fe3O4, CoFe2O4, Ni, and Co-carbon coated, with a 10 wt% content have been prepared and their morphological, electric, thermal, magnetic, and mechanical properties evaluated. Films were processed by solvent casting under two different processing conditions, no magnetic field applied during solvent evaporations, and an out-of-plane magnetic field application. It is shown that ABS-based composites preserve the magnetic properties of the filler, providing a simple way to tune the magnetic behavior in the polymer. The inclusion of permalloy, Fe3O4, CoFe2O4, Ni, and Co-carbon coated fillers, allow to obtain saturation magnetizations of 6.2, 4.1, 7.3, 3.7, 4.4, and 4.9 emu/g, respectively, and coercive fields of 88.5, 30.9, 128, 2529.8, 123.6, and 197.4 Oe, respectively. It was found that the mechanical properties of the composites depend on filler type and dimensions, maintaining the thermoplastic behavior of the matrix when the fillers are small (up to 40 nm) and losing it when the fillers are bigger (from 60 to 135 nm). Further, the breaking stress, elongation at break, and the Young's modulus are material dependent, showing higher values when the fillers are Fe3O4 and CoFe2O4 and lower values when the fillers are permalloy, Ni, and Co-carbon; for example, these values are the highest in the case of the ABS-Fe3O4 composite with values of 28.7 MPa, 4.1%, and 1266.9 MPa, respectively, while ABS-Co composite shows the lowest breaking stress and elongation at break with 9.2 MPa and 1.5%, respectively. The ABS-permalloy composite presents the lowest Young's modulus with 781.5 MPa. Also, the magnetic fillers do not change significantly the thermal, dielectric, and the electrical properties of the composites at this concentration (10 wt%). Overall, the present work demonstrates the feasibility of the modulation of the mechanical and the tuning of the magnetic properties of ABS-based magnetic nanocomposites by changing the magnetic material and by applying a magnetic field during the processing of the composites, allowing their application in areas including sensors, actuators, and magnetic devices.